In recent years, as motors became high-performance ones, there has been the development of a large number of motors with the installation of the so-called rare earth magnets [R—Fe—B based magnets wherein R represents a rare earth element such as neodymium (Nd): The same hereinafter].
Here, since the rare earth magnet is a metal magnet, it is different from a ferrite magnet comprised of an oxide, and thus, the electrical resistance of a magnet body is low. For this reason, when rare earth magnets are mounted in a motor, there is a problem that the loss resulting from an eddy current to be generated on the surfaces of the rare earth magnets during their use increases and the motor efficiency falls. In an attempt to reduce such an eddy current loss, there has been proposed a method for reducing the eddy current loss, which comprises dividing a rare earth magnet, covering the divided, individual rare earth magnets with resin coating, an adhesive, or the like, and thereby, insulating between the rare earth magnets (Patent Literature 1).